<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Pdf
 * @subpackage Fonts
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: TrimmedTable.php 18993 2009-11-15 17:09:16Z alexander $
 */

/** Zend_Pdf_Cmap */
require_once 'Zend/Pdf/Cmap.php';


/**
 * Implements the "trimmed table mapping" character map (type 6).
 *
 * This table type is preferred over the {@link Zend_Pdf_Cmap_SegmentToDelta}
 * table when the Unicode characters covered by the font fall into a single
 * contiguous range.
 *
 * @package    Zend_Pdf
 * @subpackage Fonts
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Pdf_Cmap_TrimmedTable extends Zend_Pdf_Cmap
{
	/**** Instance Variables ****/


	/**
	 * The starting character code covered by this table.
	 * @var integer
	 */
	protected $_startCode = 0;

	/**
	 * The ending character code covered by this table.
	 * @var integer
	 */
	protected $_endCode = 0;

	/**
	 * Glyph index array. Stores the actual glyph numbers.
	 * @var array
	 */
	protected $_glyphIndexArray = array();



	/**** Public Interface ****/


	/* Concrete Class Implementation */

	/**
	 * Returns an array of glyph numbers corresponding to the Unicode characters.
	 *
	 * If a particular character doesn't exist in this font, the special 'missing
	 * character glyph' will be substituted.
	 *
	 * See also {@link glyphNumberForCharacter()}.
	 *
	 * @param array $characterCodes Array of Unicode character codes (code points).
	 * @return array Array of glyph numbers.
	 */
	public function glyphNumbersForCharacters($characterCodes)
	{
		$glyphNumbers = array();
		foreach ($characterCodes as $key => $characterCode) {

			if (($characterCode < $this->_startCode) || ($characterCode > $this->_endCode)) {
				$glyphNumbers[$key] = Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;
				continue;
			}

			$glyphIndex = $characterCode - $this->_startCode;
			$glyphNumbers[$key] = $this->_glyphIndexArray[$glyphIndex];

		}
		return $glyphNumbers;
	}

	/**
	 * Returns the glyph number corresponding to the Unicode character.
	 *
	 * If a particular character doesn't exist in this font, the special 'missing
	 * character glyph' will be substituted.
	 *
	 * See also {@link glyphNumbersForCharacters()} which is optimized for bulk
	 * operations.
	 *
	 * @param integer $characterCode Unicode character code (code point).
	 * @return integer Glyph number.
	 */
	public function glyphNumberForCharacter($characterCode)
	{
		if (($characterCode < $this->_startCode) || ($characterCode > $this->_endCode)) {
			return Zend_Pdf_Cmap::MISSING_CHARACTER_GLYPH;
		}
		$glyphIndex = $characterCode - $this->_startCode;
		return $this->_glyphIndexArray[$glyphIndex];
	}

	/**
	 * Returns an array containing the Unicode characters that have entries in
	 * this character map.
	 *
	 * @return array Unicode character codes.
	 */
	public function getCoveredCharacters()
	{
		$characterCodes = array();
		for ($code = $this->_startCode; $code <= $this->_endCode; $code++) {
			$characterCodes[] = $code;
		}
		return $characterCodes;
	}


	/**
	 * Returns an array containing the glyphs numbers that have entries in this character map.
	 * Keys are Unicode character codes (integers)
	 *
	 * This functionality is partially covered by glyphNumbersForCharacters(getCoveredCharacters())
	 * call, but this method do it in more effective way (prepare complete list instead of searching
	 * glyph for each character code).
	 *
	 * @internal
	 * @return array Array representing <Unicode character code> => <glyph number> pairs.
	 */
	public function getCoveredCharactersGlyphs()
	{
		$glyphNumbers = array();
		for ($code = $this->_startCode; $code <= $this->_endCode; $code++) {
			$glyphNumbers[$code] = $this->_glyphIndexArray[$code - $this->_startCode];
		}

		return $glyphNumbers;
	}


	/* Object Lifecycle */

	/**
	 * Object constructor
	 *
	 * Parses the raw binary table data. Throws an exception if the table is
	 * malformed.
	 *
	 * @param string $cmapData Raw binary cmap table data.
	 * @throws Zend_Pdf_Exception
	 */
	public function __construct($cmapData)
	{
		/* Sanity check: The table should be at least 9 bytes in size.
		 */
		$actualLength = strlen($cmapData);
		if ($actualLength < 9) {
			require_once 'Zend/Pdf/Exception.php';
			throw new Zend_Pdf_Exception('Insufficient table data',
			Zend_Pdf_Exception::CMAP_TABLE_DATA_TOO_SMALL);
		}

		/* Sanity check: Make sure this is right data for this table type.
		 */
		$type = $this->_extractUInt2($cmapData, 0);
		if ($type != Zend_Pdf_Cmap::TYPE_TRIMMED_TABLE) {
			require_once 'Zend/Pdf/Exception.php';
			throw new Zend_Pdf_Exception('Wrong cmap table type',
			Zend_Pdf_Exception::CMAP_WRONG_TABLE_TYPE);
		}

		$length = $this->_extractUInt2($cmapData, 2);
		if ($length != $actualLength) {
			require_once 'Zend/Pdf/Exception.php';
			throw new Zend_Pdf_Exception("Table length ($length) does not match actual length ($actualLength)",
			Zend_Pdf_Exception::CMAP_WRONG_TABLE_LENGTH);
		}

		/* Mapping tables should be language-independent. The font may not work
		 * as expected if they are not. Unfortunately, many font files in the
		 * wild incorrectly record a language ID in this field, so we can't
		 * call this a failure.
		 */
		$language = $this->_extractUInt2($cmapData, 4);
		if ($language != 0) {
			// Record a warning here somehow?
		}

		$this->_startCode = $this->_extractUInt2($cmapData, 6);

		$entryCount = $this->_extractUInt2($cmapData, 8);
		$expectedCount = ($length - 10) >> 1;
		if ($entryCount != $expectedCount) {
			require_once 'Zend/Pdf/Exception.php';
			throw new Zend_Pdf_Exception("Entry count is wrong; expected: $expectedCount; actual: $entryCount",
			Zend_Pdf_Exception::CMAP_WRONG_ENTRY_COUNT);
		}

		$this->_endCode = $this->_startCode + $entryCount - 1;

		$offset = 10;
		for ($i = 0; $i < $entryCount; $i++, $offset += 2) {
			$this->_glyphIndexArray[] = $this->_extractUInt2($cmapData, $offset);
		}

		/* Sanity check: After reading all of the data, we should be at the end
		 * of the table.
		 */
		if ($offset != $length) {
			require_once 'Zend/Pdf/Exception.php';
			throw new Zend_Pdf_Exception("Ending offset ($offset) does not match length ($length)",
			Zend_Pdf_Exception::CMAP_FINAL_OFFSET_NOT_LENGTH);
		}
	}

}
